I bought my wedding dress online and saved a bundle. I never saw it in real life and never tried it on before I ordered it but the sizing chart was really accurate and I only needed to have the straps shortened and the hem shortened (apparently at 5'4" I'm much shorter than the average bride). I was worried that the dress might look cheap when it arrived, but it was gorgeous! This is the website http://www.paradisestylegroup.com/ (it's a Canadian company - i have no offiliation with them at all, I live on the opposite side of the country, I just had a really good experience with them and I love a bargain!)
I had a quick look through and couldn't find anything quite like your dream dress, but certainly there were many options which you could add the strap detailing to, as someone else suggested. (Such as this one for only $369 CND! http://www.paradisestylegroup.com/product_image.php?imageid=5539)
At the risk of offending the gal who worked at David's Bridal, I found that the alterations at the Bridal companies were ridiculously over-priced. The best deals are usually at the little-old-lady-who-does-tailoring-out-of-her-house, in my opinion. Because most of these people get business on word-of-mouth, their workmanship is usually top-notch.
Good luck and congrats!